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Old 12-10-2011, 08:28 AM
 
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Originally Posted by NightBazaar View Post
Voyager 2 should be near the star Sirius about 298000 AD.
Did NASA purposely choose Sirius (A)?

While i'll be long dead and gone however that's still cool to know that V'Ger-2 is going by that dual star system and while i'm not an ''ancient alien theorist'' however the ancient egyptians and dogons believed humans came from a dying planet orbiting Srius-B to which that in itself if a mystery as it cannot be seen by the naked eye and yet they knew of that white dwarf star and so it's always intrigued me.
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Old 12-10-2011, 10:49 AM
 
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Originally Posted by 6 Foot 3 View Post
Did NASA purposely choose Sirius (A)?

While i'll be long dead and gone however that's still cool to know that V'Ger-2 is going by that dual star system and while i'm not an ''ancient alien theorist'' however the ancient egyptians and dogons believed humans came from a dying planet orbiting Srius-B to which that in itself if a mystery as it cannot be seen by the naked eye and yet they knew of that white dwarf star and so it's always intrigued me.
I don't know if they did or not. If they did, I doubt it had anything to do with Dogon and/or Egyptian myths. If Voyager 2 manages to get anywhere near the Sirius system, "near" should be considered as being more of a relative term. The expectations are that Voyager 2 will pass within 4.3 light years from the cluster. That's not very close. We've already seen the Voyagers drift off course, and they haven't yet left the solar system.

The Dogon/Sirius-B myths might stem from "cultural contamination". A lot of the hoopla over the Dogon myths seems to come from Robert Temple's books, such as "The Sirius Mystery". His writings are based on an interpretation of the works of Marcel Gnaule and Germaine Dieterlen (from the 1930s).
http://en.wikipedia.org/wiki/Sirius#Dogon
Robert K. G. Temple - Wikipedia, the free encyclopedia

As for the Egyptians, do you actually know if the Egyptians really held a belief about Sirius-B? A quick browse of Egyptians and Sirius-B seems to show an awful lot of New Age and UFO/ET websites. I'm inclined to think much of this is based on Robert Temple's books as well as the ramblings of Erich von Daniken's own interpretation of history.

Let's say Voyager 2 actually does enter the Sirius system. Sirius-A and B are companion stars. The myth includes humans fleeing a dying planet (namely Sirius-B) how likely is it that Sirius B would have planets that existed long enough to give rise to intelligent life able to develop spacecrafts capable of traveling to our solar system? Regardless, what purpose would there be if NASA did purposely choose to send Voyager 2 there? If the planet was dying and the beings there had already fled... well, you can probably see what I mean.
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Old 12-10-2011, 05:01 PM
 
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Good info (above posting) as always NB .
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Old 12-11-2011, 01:55 AM
 
Location: US Empire, Pac NW
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I hope we find planets much closer to Earth. I think we have the technology for fusion pulsed jets and stuff like VASIMR is on the horizon (NASA has 100 people working on the integration of VASIMR like rockets on the ISS, aiming to put it on by 2014), and probably by the time I die (I'm 30 now), we will be on the verge of anti-matter engines.

Even with anti-matter, it would take approximately 40 years to do a round-trip trek to Alpha Centauri, which is a mere 1.4 ly away.

Thus, I think we should pour a lot more research into the potential for FTL drives. I'm pretty sure some new physics and math will be required for it ... or allow for current models of FTL drive to theoretically work. It's looking like the Higgs Boson doesn't exist and something else gives mass to particles in the universe. And we have discovered stuff that goes faster than light - theoretically, that shouldn't happen. But like all good theories, they may be bound for the dust bin of scientific discovery. I'm hopeful that within a few hundred years we'll have discovered something to bring us out of the cradle.

Pardon my optimistic reverie, I just really think it is cool and we should definitely map out where we want to go first prior to going there!
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Old 12-11-2011, 11:34 AM
 
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Originally Posted by eskercurve View Post
I hope we find planets much closer to Earth. I think we have the technology for fusion pulsed jets and stuff like VASIMR is on the horizon (NASA has 100 people working on the integration of VASIMR like rockets on the ISS, aiming to put it on by 2014), and probably by the time I die (I'm 30 now), we will be on the verge of anti-matter engines.

Even with anti-matter, it would take approximately 40 years to do a round-trip trek to Alpha Centauri, which is a mere 1.4 ly away.
Let's say you'll live to around 80 or 90. That's looking at 50-60 years from now for you, and tagging it by around 2062 to 2072 for the possibility of anti-matter engines. If we could develop a system that could do a round-trip system (an unmanned probe) in 40 years to Alpha Centauri, that would be very impressive. The trick is not only having fast engines, but to be able to repel anything that could collide with the spacecraft. Hitting anything, even as small as a grain of sand, the energy released from such a collision with very tiny objects at very high speeds would be enormous as well as catastrophic.

It could take much longer than 40 years, allowing acceleration to build up. A lot of it might also depend on the direction of travel to exit the solar system. Traveling vertically to the solar system could mean reducing exposure to the debris field of the accretion disk. Exactly how much debris there is out in the Oort Cloud is currently unknown. Since Earth-based communication with the probe would require very long delays, the spacecraft would need to be equipped with an AI system to make on-the-spot decisions to avoid obstacles and automatically make course corrections as needed. Well before reaching its destination, the spacecraft would have to begin braking long before reaching the destination. Once within the star system, the spacecraft would most likely remain there for an extended period of time to study what's there. Our unmanned spacecraft would likely be taking a one-way trip, which would be okay. Once there, hopefully, we'd still be in communication with the craft, even though there's be a great lapse of time. However, even if the signals take 1.5 years to reach us, they'd be frequent enough to provide an understanding of what's there, as well as how successful such a mission would be. The real question is the cost of such a spacecraft with an antimatter propulsion system. How large would such a craft have to be to utilize such a system?

Currently, a study is being conducted into the feasibility of building what's called the "DARPA 100-Year Starship Project". If a human crew were to be sent on the trip, the proposal is generally seen as a one-way trip for those onboard. It would also mean some sort of hibernation or suspended animation of the crew would be necessary. But if hibernation can be achieved, then why not study the destination for a few years while there, then return to hibernation for a trip back the Earth. That would be a really weird experience for the crew. Over 200 years would have passed by the time they got back to Earth.

Regardless of what may be envisioned for the future, it's all going to boil down to economics and just how much progress science can make. If progress is severely hindered, then it could be hundreds of years before such travel could be achieved, although I do think an unmanned probe could be done. And that would be the most practical for exploration before even thinking about sending people. I know you didn't say anything about people, but I'm throwing it in because that would be the ultimate objective.

Quote:
Thus, I think we should pour a lot more research into the potential for FTL drives. I'm pretty sure some new physics and math will be required for it ... or allow for current models of FTL drive to theoretically work. It's looking like the Higgs Boson doesn't exist and something else gives mass to particles in the universe. And we have discovered stuff that goes faster than light - theoretically, that shouldn't happen. But like all good theories, they may be bound for the dust bin of scientific discovery. I'm hopeful that within a few hundred years we'll have discovered something to bring us out of the cradle.
I fully agree that we need to steadily continue to progress if we are to reach future goals. Regarding the Higgs boson, it might turn out that it doesn't exist, but it's too early to throw it out just yet. And as for the faster that light neutrinos, that's also too early to conclude. The problem is that it's still uncertain that the results are in fact correct. Even the team who conducted the test is saying there might be errors.

If neutrinos do indeed travel faster than light, that would be a remarkable discovery. Exactly how we would apply such a discovery remains to be seen. We'd probably want to see if there are any other particles that can exceed the speed of light Probably not applicable for sending starships through space any time soon. There's a big difference between neutinos and a starship. Most likely it could be very useful for sending information over great distances. Maybe it could be useful to beam a crew great distances, but it would require, not only a transmitter, but a receiver on the other end at the destination.

If it turns out that neutrinos are not traveling faster than light speed, then we're back at square one with the photons.
http://www.nytimes.com/2011/11/19/sc...tists-say.html

Study rejects faster than light particle finding | Reuters

Quote:
Pardon my optimistic reverie, I just really think it is cool and we should definitely map out where we want to go first prior to going there!
There's nothing wrong with optimism. It's optimism that leads to new discoveries and advancement. I agree, we'd need much more information to chart out a course to the stars, in part, to note any possible obstacles. In addition, even to get to nearby stars, it's not a straight shot to get there because everything is in motion. It all has to be taken into account. It would take a lot of precise course corrections to accurately reach a target. Currently, it's hard enough just getting spacecrafts to the Moon or the planets.
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Old 12-11-2011, 10:55 PM
 
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If we were to send out some sort of SETI telecommunications message to this planet, how long would it take to reach there, 600 years?
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Old 12-12-2011, 07:50 AM
 
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Originally Posted by Winkelman View Post
If we were to send out some sort of SETI telecommunications message to this planet, how long would it take to reach there, 600 years?
Yes, because radio waves travel at the speed of light. A lot of it depends on the strength of the signal's source and the strength of the receivers. For example, as I understand it, picking up the transmissions from the Voyager spacecrafts is really pushing the limits in detect faint signals. I'm not sure how far more powerful transmissions from Earth would travel before they'd become too faint to detect. Regardless, it'd take 600 years for a transmission to reach Kepler-22b. If there was anyone there to send a reply, it'd be a 1200 year (round trip) wait for us to receive their message.
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Old 12-12-2011, 10:52 AM
 
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NB

didn't Einstein propose that when traveling at the speed of light that time slows down (Time Dilation?)

If so how much?

So for example if we had the technology to space travel at light speed would that space vessel after reaching the designated star arrive there at a different time than how we plotted that time and distance from earth?

So in other words lets say (just a wild example) it takes 5 light years to reach star A and yet when that vessel arrived there it and it's occupants had only aged 50 years do to time slows when traveling at light speed?
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Old 12-12-2011, 08:45 PM
 
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Quote:
Originally Posted by 6 Foot 3 View Post
NB

didn't Einstein propose that when traveling at the speed of light that time slows down (Time Dilation?)

If so how much?

So for example if we had the technology to space travel at light speed would that space vessel after reaching the designated star arrive there at a different time than how we plotted that time and distance from earth?

So in other words lets say (just a wild example) it takes 5 light years to reach star A and yet when that vessel arrived there it and it's occupants had only aged 50 years do to time slows when traveling at light speed?
The rate at which time slows down depends on how fast or slow something is moving through points in space. A person who is is motion will have a different result than a person who is stationary. Even though the watches of both people are syncronized and ticking at the exact same rate per second, the end result in the number of seconds that elapse for each will be different.

If we had the ability to travel at the speed of light, then it would take 5 years, not 50, to travel 5 light years. But that's not the real issue. As you approach the speed of light, time slows down, meaning you don't age as quickly. This starts getting into Special Relativity. Einstein viewed the speed of light as the maximum speed limit of anything in the universe. Whether that's true or not doesn't matter, but we'll assume it to be true for the purpose of resolving the question.

Imagine two people traveling to a destination that's 50 miles away. One person drives a car at 50 miles per hour, but the other walks at a snail pace. The person in the car will reach the destination in exactly one hour. But the person walking will take much longer. For each person, time ticks by at the same rate, but the results differ between the two. If the person traveling by car is only one hour older, he will arrive there younger than the person who is walking to the same destination.

Okay, that's kind of a lame example, but the point is that each tick of the clock at one tick per second is exactly the same for each. Since we know the distance of space, why is there a difference in time? Time is not the same for each person and is relative from each person's point of view and relative to the velocity it takes to travel the distance through space from Point A to Point B.

If I'm wrong, I'm sure someone will point it out with a correction or provide a better example.

Here's a vid that looks at the subject of time dilation that may also help.



Time Dilation | Einstein's Relativity - YouTube
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Old 12-13-2011, 12:33 AM
 
Location: US Empire, Pac NW
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Quote:
Originally Posted by 6 Foot 3 View Post
NB

didn't Einstein propose that when traveling at the speed of light that time slows down (Time Dilation?)

If so how much?

So for example if we had the technology to space travel at light speed would that space vessel after reaching the designated star arrive there at a different time than how we plotted that time and distance from earth?

So in other words lets say (just a wild example) it takes 5 light years to reach star A and yet when that vessel arrived there it and it's occupants had only aged 50 years do to time slows when traveling at light speed?
RELATIVITY CALCULATOR and

http://www.wolframalpha.com/input/?i=relativistic+time+dilation&a=*FS-_**RelativisticTimeDilationFormula.t-.*RelativisticTimeDilationFormula.to-.*RelativisticTimeDilationFormula.v--&f2=1+s&f=RelativisticTimeDilationFormula.to_1+s&f 3=2.6x10^8+m%2Fs&x=10&y=6&f=RelativisticTimeDilati onFormula.v_2.6x10^8+m%2Fs

According to relativity, say we could approach the speed of light to 90% of it. There are three relativistic effects that would happen:

1) Your mass increases by about a factor of 2.7
2) Your length increases by about the same factor
3) The amount of time experienced by an observer on the ground not on the spaceship with you is 2.7 times more than what you experience

The meaning is, if we had the ability to go 90% the speed of light, and went to the nearest star, Alpha Centauri, it would take roughly 5.5 years to get there according to a person on the Earth, but to a person on a spaceship going there, it would only take 2.75 years, assuming instantaneous acceleration and stopping.

So far, the only means we can theorize about going very fast is fusion bomblets (similar to the Orion project), solar sails with lasers being pointed at them, or antimatter engines (theoretically anyway). The fastest we know how to get to the speed of light, other than making our own radiation (like radio waves), is only around 10% the speed of light, and that's after acceleration time!

So, if we had the money (probably around $11 trillion), we could make a HUGE spaceship with nuclear bombs as propulsion, or have a 1-ton probe at the heart of a similarly HUGE sail with lasers pointing at it (about half the cost too) and get there in 60-70 years, taking into account speed up time and time necessary to slow down.



Interstellar travel is extremely hard. Either we need to have a huge leap in understanding of physics to make more technology possible, or make lifespans incredibly long through bio-engineering, or let robots explore the galaxy for us.

I much prefer having us explore it, so I fully support efforts to radically increase the human lifespan and also go faster.

An interesting factoid: GPS satellites must have their clocks updated because they experience relativistic effects as well! They are orbiting the earth at the speed of about 14,000 km / hr. That isn't very fast from a relativity standpoint, but it is enough to throw off range estimates used in calculating your position, enough that they have to correct it every once in a while!
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